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Results are reported from a study on the in vitro separation and identification of leachables from three different polymer-based dental filling materials by using a combined method of gas chromatography and mass spectrometry. The median number of separable organic leachables in these materials was between 14 and 22. Of these organic leachables the following were identified and quantified: DL-camphorquinone, 4-dimethylaminobenzoic acid ethyl ester (DMABEE), drometrizole, 1,7,7-trimethylbicyclo[2,2,1]heptane, 2,2-dimethoxy[1,2] diphenyletanone (DMBZ), ethyleneglycol dimethacrylate (EGDMA), and triethyleneglycol dimethacrylate (TEGDMA). Three of the leachables have previously been shown to provoke allergy. The range of log P(ow) values (representing the lipophilicity of these compounds) varied between 1.09 and 4.20. By multivariate data analysis, selected leachables from the tested materials were shown to separate into characteristic patterns. The results contribute to a characterization of potential hazardous compounds in polymer-based dental filling materials.

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Subepithelial soft tissue and bone obtained from the implant bed in the vicinity of stainless steel and titanium miniplates and screws were evaluated with respect to the presence of immunocompetent cells. The study included tissue specimens from 19 patients, in whom the implants (14 stainless steel and 5 titanium) had been in situ for more than 6 months. The ABC (avidin-biotin-complex) immunoperoxidase staining technique using monoclonal antibodies defining T lymphocytes (CD3+), macrophages (CD11c+) and Class II MHC (HLA-DR) was performed on EDTA demineralized, frozen bone tissue, and on fresh frozen soft tissue specimens. The results showed scattered T lymphocyte clusters, small numbers of macrophages and abundant expression of HLA-DR in the soft tissue adjacent to both stainless steel and titanium implants. There was no substantial difference in tissue reactions between implants of the two materials. The demineralized bone sections disclosed presence of immunocompetent cells in the connective tissue lining the periphery of the screw holes. Metal particles were seen in both the soft tissue and the bone specimens. We conclude that a mild tissue reaction takes place in the vicinity of miniplates and screws of stainless steel and titanium, and that the intensity of the reaction indicates that the implants are well tolerated by the host tissue.

The possibility that triclosan and PVM/MA (polyvinylmethyl ether/maleic acid) copolymer, additives to dentrifrices, could interact with eukaryotic membrane lipids was studied by two methods: first, by determining the pressure/molecular area isotherms at 37 degrees C of glycerophospholipid monolayers, using the Langmuir technique; and second, by phase-transition parameters in liposomes of the same lipids, using differential scanning calorimetry (DSC). Triclosan interacted, in a concentration-independent manner, with monolayers of saturated phosphatidylcholines (PC; i.e. markers of the outer membrane leaflet of eukaryotic cells). Triclosan and PVM/MA copolymer mixtures were shown to clearly interact in a concentration-dependent manner with PC. Triclosan was found to interact with liposomes of saturated and unsaturated phosphatidylcholines and phosphatidylserines (PS; i.e. markers of the inner membrane leaflet of eukaryotic cells), and saturated ethanolamines (PE; i.e. markers of the inner membrane leaflet of eukaryotic cells), resulting in a decrease of the lipid melting temperature (Tm). PVM/MA copolymer changed the Tm of PS, PC, and PE in different manners. By adding PVM/MA or triclosan-PVM/MA copolymer mixtures to 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine (SOPS) no lipid transitions were detected. A biphasic change of the PC transition temperature resulted when triclosan or triclosan PVM/MA copolymer mixtures were added, indicating domain formation and change of the lipid polymorphism.